Since Henry Cavendish's discovery of “flammable air” in 1766 (named “hydrogen” by Antoine Lavoisier in 1783), hydrogen is widely used in chemical synthesis, in hydro-cracking of natural hydrocarbons, in food industry, in welding, as a rocket fuel, etc. There have been a lot of efforts to develop new technologies based on the use of hydrogen in automobile and other engines, since it might provide a powerful and clean source of energy. It would improve the environment by reducing air pollution necessarily produced by burning hydrocarbon fuels, reduce people's oil dependency by limiting the consumption of oil-based products for energy generating, save natural oil, whose supply in the earth is gradually depleting, for other productive purposes, and also would drive down gasoline prices and other consumer prices dependent on the oil price.
One of the most popular such technologies is fuel cells. They utilize hydrogen for producing electrical energy (chemical reactions involve hydrogen and oxygen may produce electricity and water), which can then power electrical engines for transportation or other purposes. At present the use of fuel cells is limited by their heavy weight, necessity of additional complicated equipment, and economical reasons based on high cost of commercial hydrogen production.
Some world renown car makers (such as BMW, Mazda, etc.) propose hybrid solutions combining traditional fuels (e.g. gasoline) of internal combustion engines with hydrogen. These technologies require means for production, storage, and utilization of hydrogen in the engines. Many U.S. patents describe different devices and methods dedicated to the hydrogen and hybrid technologies.
For example, U.S. Pat. No. 4,625,681 teaches that gaseous water (probably meaning vapor) may be generated from liquid state water by a gasifier, and then the gaseous water is dissociated by multi-step electrical discharge and induction heating to generate electro-conductive plasma. The method is complicated and costly, and so far is not noticeably usable in practice.
U.S. Pat. No. 4,140,090 teaches that hydrogen may be utilized as a supplemental gaseous fuel for a precombustion chamber. “An electrolytic generator can be incorporated with the precombustion chamber mechanism for generating hydrogen and oxygen gases to operate the precombustion chamber. The electrolytic generator includes an automatic water feed system for replacing the water used to generate the hydrogen and oxygen gases and incorporates an electrode and internal pressurization arrangement for automatically shutting off the generation of hydrogen and oxygen gases on engine shut-down and for storing a sufficient quantity of hydrogen and oxygen gases to facilitate subsequent engine start-up”. The use of an electrolytic generator (electrolyzer) for continues generation of hydrogen from water usually requires significant electrical power consumption that prevents its broad usage.
Another U.S. Pat. No. 4,344,831 particularly teaches an apparatus for generation of hydrogen, including an electrolytic tank for circulating and cooling the electrolyte solution therein. It utilizes an electrolyzer to produce hydrogen and oxygen in separate compartments and further mixes them prior to entering an internal combustion engine, and thus needs plenty of electrical power for the process.
U.S. Pat. No. 5,243,025 teaches a water-to-fuel production apparatus including a tank divided into compartments: a first (cathode) compartment is for producing hydrogen, and a second (anode) compartment is for producing oxygen. The gases don't contact each other until mixed prior to entering an internal combustion engine, wherein free hydrogen is injected into the combustion chamber to stimulate combustion of more inert or slower-burning fuels. A third compartment intakes water contained in the engine's exhaust. The gaseous hydrogen and oxygen are produced by elevated temperature electrolysis of the water. The apparatus' exhaust gases, usually having a temperature about 177.degree.C. or 350.degree.F., are used for purposes of heating the electrolyzer. The use of waste heat in endothermic electrolysis improves efficiency of the overall process, but still requires substantial electrical power supply.
Another U.S. Pat. No. 6,981,367 teaches a device for generating hydrogen from an exhaust containing water vapor. The device comprises an exhaust diverter and a hydrogen generation section, including an electrolysis unit, in one of the embodiments accumulating and storing hydrogen generated by the electrolysis unit directly from the exhaust water vapor. In an embodiment the electrolysis unit is thermally coupled to an exhaust duct, providing a means by which the waste heat of the electrolysis unit can be absorbed in the exhaust gas, i.e. cooling the electrolysis unit. Therefore a portion of the electrical power used in the electrolysis process is utilized for the condensing of water from the exhaust water vapor. Understandably, this would require more electric energy.
One more U.S. Pat. No. 6,314,918 teaches a renewable hydrogen gas generating system comprising a series of components integrally connected to an internal combustion engine, voltage supplied by an alternator and specifically designed high output electrical power generating device to energize a multiple cell anode and cathode electrolyzer for liberating hydrogen at greater than 100% efficiency levels. As stated in the patent's disclosure: “The practical application of the electrolysis method has previously resulted in many less than satisfactory attempts, primarily due to insufficient hydrogen gas production. Because of the electrical power levels required to liberate the hydrogen gas, this method can only be efficient if an onboard power supply is capable of furnishing ample current for adequate gas production”.
It further states: “The Electrolyzer Unit 12 is supplied electrical current through a High Output Electrical Generating Device 60. This is accomplished when the rotations of the engine turn a Pulley 80 which spin the belt-driven OEM Alternator 48 and the belt-driven High Output Electrical Generating Device 60. As they spin, current is discharged from the power windings of the OEM Alternator 48, through a Bridge Rectifier 56, Capacitors 58, and then connecting to the power windings of the High Output Electrical Generating Device 60, through a Bridge Rectifier 64, Capacitors 66, passing through a Pressure Switch 40, and finally to the Anode Connection 14 and the Cathode Connection 16 of the Electrolyzer Unit 12. In the event of low fuel pressure upon starting the engine, an AC Power Cord 74 with an On/Off Controller 76 is included to plug into regular 110-120 V AC household current (or 220-240 VAC, where applicable) to pre-pressurize the fuel system”. Therefore, the above described system seems to typically require a start-up charging from an outside voltage source, which raises a question if it can be shut down and readily restarted, for instance in a parking space without an electrical power outlet. The second issue is a structure of the “specifically designed high output electrical power generating device”, which is not disclosed in detail in that patent's specification.
U.S. Pat. No. 6,770,186 discloses a hydrogen-fueled motor vehicle including at least one hydrogen-fueled locomotion subsystem and at least one refuelable hydrogen generator operative to supply hydrogen fuel to the hydrogen-fueled locomotion subsystem on demand. The refuelable hydrogen generator includes at least one electrochemical reactor operative to generate the hydrogen fuel from water on demand and a refueling subsystem providing at least one of water, electrolyte, hydrogen, a metal containing material and electrical power to the electrochemical reactor. That invention particularly concerns with the refueling of the system.
A U.S. patent application publication 20020179454 A1 describes an electrolysis cell using “electrodes constructed of expanded nickel to generate gas, and includes a region designated as an electrolytic fog. A fan and condenser help lower the temperature of the gas and reduce moisture. The electrolysis is further enhanced by regulating the power input to the cell. In this way the device of the present invention produces an adequate supply of gas to aid combustion. The device delivers the gas to the engine under pressure, thereby ensuring a constant flow even when the air intake pressure is high due to turbocharger boost. The gases are continuously available, aided by a separate on-board water supply that automatically replenishes the cell when needed. The device contains both heating and cooling features that enable gas to be generated in extreme weather conditions. The only operator maintenance required is to occasionally refill the water supply.”
The descriptions and drawings of the above enumerated U.S. patents are available from the official website of the U.S. Patent and Trademark Office presently named “http://patft.uspto.gov/netahtml/srchnum.htm” by inserting their numbers in the search box and getting search results, whereas the descriptions and drawings for the patent application publication may be found on another U.S. PTO official website, at the present time named: “http://appft1.uspto.gov/netahtml/PTO/srchnum.html”.
Therefore the technologies of hydrogen producing and utilization of hydrogen-containing fuels in engines remain to be promising, and, on the other hand, need new solutions to become technically viable and commercially practical.